There are a lot of 'lost cities' under the world's lakes and oceans. Some are in the Black Sea and they date to the days of Noah. And who hasn't heard of Atlantis?
Underwater archeologist Frank Goddio dedicated his life to searching for remnants of lost relics of the ancient world. The sunken city of Heracleion-Thonis was lost to the sea a long time ago. The best guess is that the city sank in the 3rd or 2nd century BC, probably due to liquefaction of the Nile Delta silt that it was built on following one or more earthquakes.
Standing at the strategic maritime entrance to Egypt, the city was known as a port of embarkation and taxation. It was also a source of revenue for various temples. If you were a foreigner who wanted one of the God's blessings as you traveled against the current, up the Nile, offering to the deity made perfect sense.
Since 2000, Frank Goddio has been pulling architectural treasures out of the Nile silt. The city is only under about 30 feet of water, which makes recovery practical.